Image copyrightPaul LeithImage caption
Paul Leith learned about making things with felt from his wife, Tina

Used to pencils and paint - not pixels - one of London's top commercial illustrators was left behind by the digital age. But he never stopped creating and his life's work is on show in a new exhibition.

Some of the biggest brands of the 1970s, '80s and '90s wanted Paul Leith's illustrations.

He was commissioned by British Rail, BT, Mercedes, Cadbury's, Boots, The Body Shop, Royal Mail, British Airways, Radio Times and endless publishers, newspapers, magazines, supermarkets and shops.

"I never stopped," he says.

"I never turned down work. I didn't want to say no because somebody else would get it - and they might get all my work."

Image copyrightRadio Times/Paul LeithImage caption
This illustration prompted a letter in the following week's Radio Times from the TV writer for The Sun on the topic of bus conductresses

He would agree to unfeasible deadlines. Then the client would ring, asking if the work was ready.

"I used to say yes - and it wasn't," he said.

The courier would be stalled by Leith's wife, Tina, offering cups of tea and biscuits as Leith, upstairs, "desperately tried to finish" the piece, drying the paint with a hairdryer.

"Sometimes I'd work all night, through the night, I was absolutely exhausted and I'd have to carry on the next day," he says.

He worked his way from one commission in a week to six a day.

Tina would help cut out the stencils he often used. Neighbours were also roped in.

Image copyrightPaul Leith/Mercedes Image caption
As illustration became more and more in demand, Leith felt he "was on the crest of a wave of fashion"

But it was not enough. He was so in-demand clients asked other illustrators to copy him. Even Leith's own agent hired someone to imitate his style, he says.

So similar were they, "quite a few times" their work was returned to Leith by mistake.

Leith's daughter, Lydia, remembers him working all the time - even at their holiday house in Middleton-in-Teesdale in County Durham.

But it was fun spotting his wine labels in Asda and sweet packets in Boots, she says.

Leith, too, liked shelf spotting.

"Nothing equalled the first one I did for New Society; I did three covers for them," he says.

"I was so chuffed to walk into Smiths and see it on the shelf and I'd go to another Smiths and have another look."

Image copyrightPaul Leith/Royal MailImage caption
Leith was commissioned by Royal Mail to design four stamps to commemorate the 150th anniversary of Kew Gardens

Born in South Shields, Leith trained at Sunderland College of Art but then moved to London.

It was the "fashionable thing to do" in 1965.

At the Royal College of Art, Sir Quentin Blake - minus the knighthood in those days - was one of his tutors.

"I didn't think he was very good, myself, at the time - show's you how stupid you can be," Leith says.

His former teacher thinks Leith has "an unusual talent".

"I don't think I have ever seen anything quite like it and I still admire it now in its more recent manifestations," Sir Quentin said.

Image copyrightPaul LeithImage caption
Leith's former agent Jacqui Figgis says he did all "the most innovative authors' covers"

Leith started with Cumberland pencils, before moving on to hand cut stencils and acrylic paint.

In his book Fifty Years of Illustration Lawrence Zeegen called him "particularly influential".

"Leith's ability to visually express clever ideas in compelling images set his work apart from many other illustrators of the time," he says.

Image copyrightPaul LeithImage caption
Jacqui Figgis says Leith was "cutting edge" and "pulled the rabbit out of the hat every time"

Pre-computers, rough versions of Leith's work had to be faxed to clients in sections and joined up at the other end.

Finished work would be collected by courier or posted.

At one point, he was doing so well he bought a new motorbike but, by the end of the year, had not had time to ride it.

He was "crazy about motorbikes", he says, and eventually collected 12 vintage models.

He "only" has six now, he says.

"When you're sitting at your desk all day it's nice to jump on your motorbike and go fast," he says, emphasising the word with evident relish.

"From being completely static to going fast, that's the thing," he laughs.

Image copyrightPaul LeithImage caption
Leith has created collages using an assortment of papers and materials

Leith might have been willing to embrace the fax and quite happy to take an engine apart, but computers held no interest.

Faced with his inability to use this modern technology, commercial clients "got somebody else".

So he left London - which was not swinging anymore and no longer had Jimi Hendrix and Pink Floyd playing in little rooms - and he moved to Cumbria.

These days he is "super happy", doing what he chooses instead.

Image copyrightPaul LeithImage caption
Leith is a prolific sketcher

As he sketches people come and talk to him, offering mints, coffee and crisps.

He is pleasantly surprised by the unexpected approval of "frightening yobs" and resigned to the comments of passing amateur art critics, whose wives can do "better than that".

He has "no interest in being taught" but he makes an exception for Tina.

"She's on my side," he laughs.

It was Tina who opened up a new element to his work by showing him how to bond felt to material and do chain stitch and blanket stitch.

"But I forgot that," he says.

"I can't learn things like that so I just do rubbish stitch, which I prefer anyway."

Image copyrightPaul Leith/Lydia LeithImage caption
Transforming two 1970s concrete subways at Hardwicke Circus in Carlisle, Leith found people walking past "after a few days they started to say hello - they always wanted to chat".

He learned out of necessity: she had made a large picture he liked, but gave it away.

When asked to make him another one her reply was along the lines of "do it yourself". So he did.

His felt pieces - which led to colourful and vibrant public murals at Hammond's Pond, Talkin Tarn and Hardwicke Circus in Carlisle - will be shown at the exhibition for the first time.

"I am grateful that I got work as an illustrator but I've always preferred and wanted to do my own things," he says.

"I've always slightly resented being told what to do."

Image copyrightLydia LeithImage caption
Works in felt chronicle the city of Carlisle

Image copyrightPaul LeithImage caption
Leith's wife Tina taught him about iron-on adhesive for material, which he prefers to complicated stitches

Paul Leith: Technicolour Carlisle at Tullie House Museum and Art Gallery, Carlisle runs from 27 May to 1 October.